﻿/*
         /// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="file">来自form表单的文件信息</param>
        /// <returns></returns>
        [HttpPost, Route("Upload")]
        public ActionResult Upload([FromForm] IFormFile file)
        {
            return Ok(new {newFileName=ImgHelper.Upload(file) });
        }
*/

using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;

namespace BWShop.Common
{
    public class ImgHelper
    {
        /// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="file">来自form表单的文件信息</param>
        /// <returns></returns>
        public static string Upload(IFormFile file)
        {
            string rootdir = AppContext.BaseDirectory.Split(@"\bin\")[0];
            string fname = DateTime.Now.ToString("yyyyMMddHHmmssffff") + System.IO.Path.GetExtension(file.FileName);
            var path = rootdir + @"\Upload\" + fname;
            using (System.IO.FileStream fs = System.IO.File.Create(path))
            {
                file.CopyTo(fs);
                fs.Flush();//清空文件流
            }
            //生成其他规格缩略图
            //生成200*200的
            //源图路径（物理路径）
            var originalImagePath = path;
            //缩略图路径（物理路径）
            var thumbnailPath = rootdir + @"\Upload\" + fname + "_200x200.jpg";
            //调用生成缩略图方法
            MakeThumbnail(originalImagePath, thumbnailPath, 200, 200, "HW");
            //生成400*400的
            //源图路径（物理路径）
            //缩略图路径（物理路径）
            thumbnailPath = rootdir + @"\Upload\" + fname + "_400x400.jpg";
            //调用生成缩略图方法
            MakeThumbnail(originalImagePath, thumbnailPath, 400, 400, "HW");

            return "http://localhost:8081/" + fname ;//将能访问新文件的网址回传给前端


        }
        #region  生成缩略图 
        ///<summary> 
        /// 生成缩略图 
        /// </summary> 
        /// <param name="originalImagePath">源图路径（物理路径）</param> 
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param> 
        /// <param name="width">缩略图宽度</param> 
        /// <param name="height">缩略图高度</param> 
        /// <param name="mode">生成缩略图的方式</param>     
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode )
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;

            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形）                 
                    break;
                case "W"://指定宽，高按比例                     
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例 
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）                 
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片 
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板 
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法 
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度 
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充 
            g.Clear(Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分 
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
             new Rectangle(x, y, ow, oh),
             GraphicsUnit.Pixel);

            try
            {
                //以jpg格式保存缩略图 
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                //outthumbnailPath = thumbnailPath;
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
    }
}
#endregion